Technical Abstract:
Chlorine (Cl) solutions of 100-200 ppm are the standard by which post-wash shell egg sanitizers are measured. Any facility that packages eggs with the USDA grade shields must use a comparable sanitizer. While chlorine solutions are inexpensive, non-corrosive, and safe to handle, they are not very effective after coming into contact with shell egg wash water which has a pH 10-11 and always contains organic material such as feed, shells, and egg meat; all of which decrease the effectiveness of chlorine. A study was conducted to determine the efficacy of post-processing sanitizing rinses on several microbial populations associated with egg shells immediately after washing and during 5 w of 4 C storage. After eggs were washed for 1 min by spraying with water heated to 49C and pH 11 wash water, eggs were treated with one of the following 52C sanitizing rinses: water, 100 ppm Cl, 200 ppm Cl, 50 ppm electrolyzed water or 200 ppm peracetic acid. A control group of unwashed nest run eggs was also evaluated. The experiment was performed three times. Each replicate was evaluated on the day of processing and weekly for five weeks of 4 C storage. Microbial populations enumerated were: Aerobic microorganisms (AM), Enterobacteriaceae (ENT), and yeasts/molds (YM). Eggs which were not washed had the highest counts for the three populations monitored. None of the sanitizers tested were more effective than rinsing with water. These data indicate that while washing reduced AM, ENT, and AM by 90-99.9%, the sanitizing rinses tested in this study were unable to elicit a further reduction in the numbers of microorganisms associated with the egg shells and membranes of washed eggs.